The chronic ingestion of alcoholic beverages has been demonstrated to be associated with an increased incidence of bacterial infections which are generally more severe in nature than in the non-alcoholic. These well known clinical observations denote the presence of as yet undefined alcohol-mediated alterations in host defense mechanisms. The research project is to define the basis of the alcohol mediated alterations in host defense mechanisms whereby increased proneness to infectious episodes is manifested during periods of alcohol abuse. Studies will be continued regarding the influence of acute and chronic ethanol ingestion, including the use of both laboratory ethanol and alcohol beverages on phagocytic expression of the reticuloendothelial system. The reticuloendothelial system is a major cellular basis of host defense. Employment of alcoholic beverages will be undertaken to delineate the possible influence the congener content of the beverage may have on functional activity of the reticuloendothelial system. Additional studies will be conducted employing vaporization techniques of Goldstein in which rats will be exposed to alcohol vapors to induce development of alcohol tolerance as well as possible liver dysfunction. The influence of prolonged ethanol exposure on macrophage and lymphocyte function will be ascertained. Studies will also be conducted on status of humoral immunity as well as cell mediated immunity in animals maintained on chronic ethanol and alcohol beverage diets for a 21 day period of time. These studies will allow a comprehensive assessment of host defense mechanisms in the alcoholic and provide a possible explanation for increased incidence of infections in alcoholic subjects.